In response to expanding urban development, the use of Lake Michigan and other sources for public water supplies, and a growing interest in regional water resources development, this report provides a detailed discussion of groundwater withdrawals and water levels in northeastern Illinois. The water-level portion of this report covers a 15-county area from Lake Michigan to north-central Illinois and from the Wisconsin border south to Kankakee County. Particular emphasis, however, has been given to deep well pumpage in the eight counties of the Chicago region because of the significant shift in the late twentieth century from groundwater supplies of the deep bedrock aquifers to Lake Michigan and other sources. This report details the fall 2000 water-level measurement of wells reaching to the St.Peter and Ironton-Galesville sandstones (deep bedrock aquifers), provides a map illustrating the slope of groundwater levels, and compares the fall 2000 levels to the fall 1995 observations. The rapid decrease in groundwater pumpage from the deep bedrock aquifers during the 1980s initially resulted in a rapid recovery of groundwater levels. However, the rate of water-level change has slowed since the mid-1990s. The greatest recovery during the past five years occurred in Cook County. Groundwater levels in several wells were observed to have risen more than 50 feet since 1995. Where the deep bedrock aquifers of Cambrian-Ordovician age continue to be used, declines in groundwater levels were observed. Most notable declines were in southeastern Kane and northern Kendall Counties, southwestern Lake County, and southeastern McHenry County. Outside the Chicago region, water-level declines were observed in deep wells at Loves Park in Winnebago County and in the vicinity of DeKalb and Sycamore in DeKalb County.
In the East St. Louis vicinity, the Illinois Department of Transportation, Division of Highways (IDOT) owns 55 high-capacity wells that are used to maintain the elevation of the ground-water table below the highway surface in areas where the highway is depressed below the original land surface. The dewatering systems are located at five sites in the alluvial valley of the Mississippi River in an area known as the American Bottoms. The alluvial deposits at the dewatering sites are about 90 to 115 feet thick and consist of fine sand, silt, and clay in the upper 10 to 30 feet, underlain by medium to coarse sand about 70 to 100 feet thick. The condition and efficiency of a number of the dewatering wells became suspect in 1982 on the basis of data collected and reviewed by IDOT staff. Since 1983, IDOT and the Illinois State Water Survey (ISWS) have conducted a cooperative investigation to more adequately assess the operation and condition of the wells, to attempt to understand the probable causes of well deterioration, and to evaluate rehabilitation procedures used on the wells. Work conducted during FY 95 (Phase 12) included monitoring the rehabilitation of four wells, step-testing the rehabilitated wells and checking the discharge from two wells for sand pumpage, checking the quality of the water discharged during the step tests, and monitoring the ground-water levels at the dewatering system sites. Posttreatment step tests were used to help document the rehabilitation of four dewatering wells, Interstate-70 (I-70) Wells 3A, 5, 11A, and 15, during FY 95 (Phase 12). Chemical treatments used to restore the capacity of these four wells were moderately successful. The improvement in specific capacity per well averaged about 103 percent based on data from pre- and posttreatment step tests. The specific capacity of I-70 Well 15 was restored to about 109 percent of the average observed specific capacity of wells in good condition at the I-70 site and the other three wells were restored to about 72 to 87 percent of the average observed specific capacity for wells in good condition. The sand pumpage investigation conducted during the posttreatment step tests on I-70 Wells 3A and 11A showed little or insignificant amounts of sand in the portable settling tank after the step tests. The tank was required to divert the discharged water into the stormwater drainage system during the other two step tests, precluding a check for sand pumpage.
The Illinois Climate Network (ICN) consists of 19 automated weather stations operated by the Illinois State Water Survey. Stations are located on the University of Illinois Agricultural Experiment Station Farms, the Southern Illinois University Agronomy Experiment Farms, and on community college campuses around the state. The ICN is part of the Water and Atmospheric Resources Monitoring (WARM) Network, which also collects information on soil moisture, groundwater, surface water, and suspended stream sediments. The ICN data have been used for agricultural purposes, such as for irrigation scheduling and to evaluate the progress of insect and crop development during spring and summer. The Illinois Department of Agriculture frequently requests the wind data when evaluating spray drift complaints. The ICN data are also used to assess the potential for using solar radiation and wind as alternative energy sources in Illinois. At each station a 10 meter tower equipped with weather instruments records hourly average air temperature, relative humidity, solar radiation, wind speed and direction, barometric pressure, and soil temperatures at 10 and 20 centimeters. Detailed descriptions of station sites are presented, including areal photographs of a 1,000 meter radius of each station. Hourly wind speed mean and variances were used to estimate the effect of obstructions around the weather towers on wind flow at each tower. Total hourly precipitation and hourly standard deviations of each weather variable are also recorded. The barometric pressure, including hourly maximum and minimum pressures and the time of the maxima and minima, have been recorded since early 1992. Daily data that are saved include maximum and minimum air temperature, maximum and minimum relative humidity, maximum and minimum soil temperatures, maximum wind gusts and direction, and their times of occurrence. The data are automatically retrieved from the stations once each day between midnight and 4:00 a.m. At least three times a week, a database management technician checks the data for quality control, and then the data are made available to the public on the Midwestern Climate Center's Midwestern Climate Information System.
The Vermilion River and Little Vermilion River watersheds lie in seven counties in east-central Illinois and west-central Indiana. The drainage areas of the Vermilion River and Little Vermilion River at their confluences with the Wabash River are 1434 and 244 square miles, respectively. The Vermilion River meets the Wabash River at river mile 257.4 and has three tributaries: North Fork, Middle Fork, and Salt Fork. The Little Vermilion River is a direct tributary of the Wabash River at river mile 247.8. Lake Vermilion, a 660-acre impounded reservoir located on the North Fork Vermilion River, is the main municipal drinking water supply for the City of Danville, Illinois. The Little Vermilion River is the main tributary for the 63-acre Georgetown Reservoir, the municipal drinking water supply for the community of Georgetown, Illinois. Approximately 88 percent of the watersheds for both rivers are in agricultural production with approximately 5 percent in forest/woodlands and wetlands. The Illinois State Water Survey (ISWS) conducted a two-year watershed monitoring study of the Vermilion River and Little Vermilion River watersheds for the Vermilion River Ecosystem Partnership-Conservation 2000 Ecosystem Program. The purpose was to assist the partnership by establishing a baseline of hydrologic and water quality data to provide a better understanding of the cumulative impacts of future best management practices implemented in the watersheds. The ISWS established a streamgaging station on the Little Vermilion River near Sidell and monitored the hydrology, sediment, and nitrate-nitrogen (nitrate-N) there and at three U.S. Geological Survey (USGS) streamgaging sites in the Vermilion River watershed (Middle Fork Vermilion River above Oakwood, North Fork Vermilion River near Bismarck, and Vermilion River near Danville). Annual sediment loads for the three Vermilion River watershed stations were approximately three times higher than loads at the Little Vermilion station. The Middle Fork station had the highest sediment loads among the three Vermilion River stations for both project years. The North Fork station had the highest annual nitrate-N load for both monitoring years. In general, annual sediment and nitrate-N loads were lower during the first monitoring year, due to below average spring season runoff. Sampling for three pesticides (atrazine, alachlor, and metolachlor) was done on a weekly basis from June to October 2002. Atrazine was the only pesticide detected during this period. The highest level sampled was 20.93 micrograms per liter (and#956;g/L) and, and all others were below 2.65 and#956;g/L.
Soil erosion and nonpoint source pollution runoff rates are estimated using output from the Revised Universal Soil Loss Equation (RUSLE). The underlying influence of climate on surface transport processes as represented in the RUSLE is carried within one constant, the R-factor. It has been assumed that the R-factor is temporally stationary; that is, it does not change with time. The purpose of this study was to process climate information from the most recent decades to update the R-factor, to examine the nature of precipitation variation and change and their impacts on the R-factor over space and time, and, specifically, to test the hypothesis that storm erosivity and the R-factor are temporally stationary. This was addressed by developing a database of precipitation data and related information needed to calculate single-storm erosivity and cumulative R-factor for each half-month of the year and for the total year. In addition the 10-year, single-storm erosive index for each station is provided. The R-factor, a nonlinear, cumulative measure of the erosive energy contained in storm precipitation, was calculated directly from 15-minute rainfall data. However, because of some undocumented quality difficulties with the 15-minute data, single-storm erosivity index statistics for accumulation into R-factors were calculated from more reliable daily data through the use of a power law transfer function. These new R-factors were tested for spatial covariation, which was found to be minimal in even terrain, and related to the limited amount of station R-factor data from past studies. Comparison with past R-factor studies indicated strongly that the methodologies used adequately duplicated old R-factors based on data from the 1930s to the 1950s. General increases observed in R-factors in this study were related to increasing amounts of precipitation and storms with rainfall greater than 12.7 millimeters, especially in the western United States. Mean seasonal patterns of storm precipitation total, duration, intensity, 30-minute and 15-minute maximum intensity, kinetic energy, erosivity, and the numbers of storms also were mapped for the conterminous United States. These analyses showed distinct patterns of precipitation change with seasons and identified regions of strong gradients where climate change first may be noticed. Trend analyses of storm precipitation variables over the 1971-1999 period indicated the lack of temporal stationarity of storm characteristics. Storm duration changes were especially an important cause of the observed changes in storm precipitation totals. However, storm trends in 30-minute maximum intensity seemed to be more important in changing the patterns of storm erosivity. Examination of storm characteristic response to interannual and interdecadal variations also indicated that storm characteristics were responding at these time scales to large-scale climate system forcings. In the winter season, atmospheric teleconnections such as the Pacific/North American Pattern and the North Atlantic Oscillation were shown to influence not only storm track positions and the number of storms at a location, but also the characteristics of individual storms. El Nio and La Nia events of the Southern Oscillation (ENSO events) had distinctive impacts on storm variables in every season of the year. Even the Pacific Decadal Oscillation showed a clear effect on storm characteristics, especially in the western United States. The results of R-factors derived from modern data compared to previous R-factors combined with storm characteristic trend and variability studies indicate conclusively that storm precipitation characteristics change sufficiently over time to warrant an evaluation of the necessity to recalculate R-factors on a regular basis.
As part of a study to estimate corn and soybean yields using satellite remote sensing techniques, biomass measurements, ground-level spectral measurements, and weather and energy flux measurements were taken at three locations in McLean County, Illinois. The locations were near Colfax, Lexington, and Stanford, Illinois. Plant samples and leaf area measurements were taken during the weeks of 12-17 June, 26-30 June, 10-14 July, 31 July-4 August, and 14-18 August 2000 in McLean County, Illinois. Corn plants were separated into leaf, stem, husk, and ear components, and soybean plants into leaf, stem, and pod components. The wet weights of the different plant parts were determined. To determine the plant dry biomass, the plant parts were dried in an oven until there was no weight change over two consecutive days. Leaf area for both corn and soybean canopies was measured using a LiCor-2000 instrument. Corn leaf area was also determined by manual measurements of leaf length and width. The smallest corn and soybean plants were at the Lexington location. The largest corn plants were at Colfax, and the largest soybean plants were at Stanford. The smaller plants at Lexington were a result of sandier soils containing less organic matter than the soils at either Stanford or Colfax. Although final yield was not measured as part of this sampling protocol, the size of the plants would indicate that Lexington should have the smallest corn and soybean yields, while the highest corn yields should have occurred at Colfax, and the highest soybean yields at Stanford.
This report on the 1993 flood on the Mississippi River in Illinois and on the lower reaches of the Illinois River was prepared by the Illinois State Water Survey with assistance from the Illinois Department of Transportation/Division of Water Resources and the Illinois Natural History Survey. The report begins with a brief description of the physical setting of the Upper Mississippi River System, including historical facts on climate, precipitation, hydrology, and floods. The 1993 flood is discussed with regard to precipitation, soil moisture, stages, flows, levee breaches, and discharge through levee breaches. Also discussed are impacts of the flood on social, economic, hydraulic and hydrologic, and environmental aspects of the river and its residents. Impacts on water quality, the environment, and public water supplies, including the beneficial and detrimental aspects of the flood, also are included. The lessons learned from this flood focus on the performance of the levees, governmental responses, the effects of flood fighting, change in stages due to levee breaches, flood modeling, and the lack of information dissemination to the public on the technical aspects of the flood. These lessons point out information gaps and the need for research in the areas of hydraulics and hydrology, meteorology, sediment transport and sedimentation, surface and groundwater interactions, water quality, and levees. The report presents a comprehensive summary of the 1993 flood as far as climate, hydrology, and hydraulics are concerned.
The Illinois River is at a crossroads. All the events in its history, both natural and those accomplished through human intervention, are now poised to change the river in ways that may render it unrecognizable in our own lifetimes. This publication is intended to introduce you to the Illinois River and the issues that will shortly determine its very survival.
The Illinois State Water Survey (ISWS), under contract to the Imperial Valley Water Authority (IVWA), has operated a network of rain gauges in Mason and Tazewell Counties since August 1992. The ISWS also established a network of groundwater observation wells in the Mason-Tazewell area in 1994. These networks are located in the most heavily irrigated region of the state. The region's major source of water for irrigation and municipal, industrial, and domestic water supplies is groundwater pumped from thick sand-and-gravel deposits associated with the confluence of two major ancient river valleys, the Mississippi and the Mahomet-Teays. Recent extreme weather events (e.g., the drought of 1988 and the great flood of 1993) resulted in large fluctuations in groundwater levels in the Imperial Valley area. The rain gauge network and the groundwater observation well network collect long-term data to determine the rate of groundwater level decline in dry periods and during the growing season, and the rate of groundwater level recovery during recharge periods. This report presents data accumulated from the rain gauge and observation well networks since their inception through August 2001. Precipitation is recorded continuously at 20 rain gauges for each storm that traverses the Imperial Valley. Groundwater levels at the 13 observation wells are measured the first of each month. The database from these networks consists of nine years of precipitation data and seven years of groundwater observations. At the beginning of groundwater observations in late 1994, the water levels were at their highest in the seven years of observation. These high groundwater levels were the result of the very wet 1992-1995 period when annual precipitation was above the 30-year normals at both Havana and Mason City. From September 1995-August 1997, precipitation in the region was well below the 30-year normal followed by the 1997-1998 and 1998-1999 observation years with rainfall totals slightly above and slightly below normal, respectively. Groundwater levels in the observation wells reflected the multi-year rainfall patterns, showing a general downward trend during dry years, a recovery in wet 1997-1998, and a leveling off in near-normal 1998-1999, followed by declines in dry 1999-2000. Despite a dry July, near-normal precipitation in 2001 brought a return to more typical seasonal hydrographs. This report includes new regression analyses of data collected through August 2001, similar to regression analyses first conducted on data collected through August 1998. The analyses indicate that groundwater levels are affected by precipitation in the Imperial Valley area and, for wells close to the Illinois River, by river stage. Generally, water levels in wells follow antecedent precipitation and Illinois River stage by one to two months; e.g., a high correlation between June groundwater levels and the Illinois River stage or precipitation that occurs in April or May. However, additional data collected since 1998 did not improve the results of the regression analyses. In fact, coefficients of determination for many regressions worsened. This suggests that regressions of observed groundwater levels versus river stage and precipitation are not adequately describing all the variables affecting groundwater levels. Using the data collected to verify, test, and improve the existing Imperial Valley groundwater flow model is highly recommended. Continued data collection also is recommended to create long-term data sets of precipitation and groundwater levels for use in modeling analyses. Collection of additional groundwater level and irrigation pumpage data also is highly recommended.
This circular presents basic information needed to plan and develop a domestic groundwater supply. A logical step-by-step planning summary is outlined. Accepted and recommended methods for a prospective owner of a domestic well to determine his water requirements and to gather meaningful information for planning his supply are presented. Also included are brief discussions on the occurrence, movement, availability, and quality of groundwater in Illinois, and the commonly used types of wells and pumps.